Numbers / 660
The Number 660
660 is composite: factorization 2^2 × 3 × 5 × 11. That gives 660 exactly 24 divisors: 1, 2, 3, 4, 5, 6, 10, 11, 12, 15, 20, 22, 30, 33, 44, 55, 60, 66, 110, 132, 165, 220, 330, 660. 660's proper divisors total 1356, 696 more than 660 itself, so 660 is abundant. 660 has a digit sum of 12; for 660, the digital root works out to 3. 660: 2, 3, 4, 5, 6, 10, 11, 12 all divide 660 evenly, out of 2-12. 660 is 1010010100 in binary and 294 in hex; as a Roman numeral it's DCLX.